Question

what will happen if both the characters present in f1 generation pass together in F2 generations

Answer 1

law of independent assortment will not work
law of independent assortment. the principle, originated by Gregor Mendel, stating that when two or more characteristics are inherited, individual hereditary factors assort independently during gamete production, giving different traits an equal opportunity of occurring together.

Answer 2

here it is said it is both the characters so it seems to be a hybrid cross.if they pass together then they will not follow the law of segregation.if this happens the traits of F1 gen (Xx Yy) . this means that the recesive trait will not be able to show  its effect in the next generation. the F2 generation will be same as F1 generation as the characters pass together so there is no assortment of genes